Summary

This trial is designed to provide evidence of the efficacy of glutathione supplementation
and health(GSH) and includes the assessment of both short term and long term effects. Based
on previous laboratory animal studies and clinical data, the investigators anticipate that
the effects of oral GSH supplementation will be progressive and cumulative. The study will
also allow for the evaluation of effects of withdrawal of the supplement on the outcome
variables.

Primary Outcomes

Secondary Outcomes

Evaluations will be carried out to expand the above comparison by including adjustments for potential prognostic factors.

time frame:
6 to 7 months

Eligibility Criteria

Male or female participants from 30 years up to 79 years old.

Inclusion Criteria:
- Healthy male and females between the ages of 30 and 79 years of age
- Not taking glutathione as a dietary supplement
- Not taking high dose antioxidant supplement prior to 1 month
- Baseline blood glutathione level of < 1 mmol/L
Exclusion Criteria:
- History or evidence of disease including cancer, diabetes, heart disease
- Subjects who smoke

Additional Information

Official title

Effect of Oral Glutathione Supplementation on the Levels of Blood Glutathione and Markers of Oxidative Stress in Healthy Adults (Glutathione Supplementation and Health (GSH) Study)

Principal investigator

John P. Richie, Ph.D.

Description

This is a randomized double-blind, placebo-controlled study in which the treatment
allocations will be kept sealed until the final statistical evaluation. The design will
include the recruitment of 60 healthy subjects (30-79 yr of age) randomized into 3 groups.
A total of 48 subjects, 16 per group will be required based upon power calculations and
results from a previous clinical trial with selenium. An additional 4 subjects per group
will be placed on trial to account for possible attrition or non-compliance. Blood, urine
and exfoliated buccal mucosal samples will be obtained from all subjects at baseline.
Questionnaire data on usual dietary intake will also be obtained at baseline. Eligible
subjects will be required to have not have taken any high dose antioxidant supplements for
at least 1 month prior to the study. Subjects will then begin supplementation according to
the following schedule:
Group A, GSH (500 mg, 2 times daily); Group B, GSH (125 mg, 2 times daily); Group C, placebo
(2 times daily). Eligible participants who sign the informed consent will be randomly
assigned to either placebo or high or low dose Glutathione groups. Participants will be
asked not to consume any other high-dose vitamin, multi-vitamin, or mineral supplements
containing glutathione throughout the study in order to prevent variation in dose of
supplemental GSH between subjects. Supplementation will continue for 6 months with
biological samples collected at 1, 3 and 6 months after baseline. At 6 months,
supplementation will be discontinued. A final collection of biological samples will occur 1
month afterwards. Compliance will be monitored by pill count.
Levels of glutathione will be measured in plasma, lymphocytes, and red blood cells as well
as in exfoliated buccal mucosal cells. Biomarkers of oxidative stress will include blood
levels of glutathionylated proteins and 8-isoprostanes and urine levels of
8-hydroxydeoxyguanosine. Glutamylcystine ligase and GST activities, and C-reactive protein
will be determined in blood. Immune function biomarkers will be analyzed including t-natural
killer cell cytotoxicity, lymphoproliferation, neutrophils phagocytosis, neutrophil
respiratory burst assays.

Trial information was received from ClinicalTrials.gov and was last updated in September 2014.